The present invention relates to a carriage assembly for a printer and in particular a detachable carriage assembly which can be quickly and easily detached and replaced as necessary. It should be understood that while the invention relates to a carriage assembly for any types of a printer, it will be discussed herein in relationship to a typewriter as the particular type of printer in which the invention is used and, therefore, whenever the word typewriter is used hereinafter, it is intended to cover all types of printers.
The prior art carriage assembly for typewriters are attached to the typewriter frame in a very complicated and unwieldy manner. The carriage mechanism is integrally formed with a pulley support assembly and may include the daisy wheel or other print mechanism, the motor to drive the print mechanism, the solenoid to cause the print mechanism to engage the platen holding the paper, the ribbonholder and ribbon winding mechanism, any ribbons used for erasure, any electrical circuits for driving the electronics on the print mechanism, and other mechanical or electrical equipment. Further, since the carriage assembly usually moves on parallel horizontal shafts, bearings must be utilized on those shafts and as the bearings wear through use, and it becomes necessary to replace them, or if for any reason the carriage has to be removed, the entire carriage assembly and pulley support assembly must be removed and replaced and the cables removed and the procedure by which this is accomplished is very time consuming and complex. In such cases, the cable tension must be readjusted. In other cases, the shaft or shafts on which the pulley support assembly and combined carriage assembly ride must be removed entirely in order to remove the carriage assembly. This is also a complex and time consuming procedure.
The present invention overcomes the disadvantages and complexities of the prior art by providing a carriage assembly having all the elements thereon as described above and yet which is detachably mounted on a pulley support assembly movably coupled to one of two spaced supports and slidably attached to a bearing assembly slidably mounted on the other of said spaced supports. Thus simply by removing two screws which hold the carriage assembly to the pulley support assembly, the carriage assembly may be lifted off the pulley support assembly and slidably removed from the bearing assembly on the other parallel support, the electrical cable disconnected and the entire unit removed and replaced in like manner in simply a matter of minutes.
Further, the pulley support assembly on which the carriage assembly rides has an adjustable bearing by which it is mounted on the first parallel support whereby, as wear occurs, the bearing can be adjusted and tightened without having to remove the pulley support assembly.
Further, the pulley support assembly has its own cable drive system which moves the pulley support assembly in a horizontal plane parallel to the cylindrical platen thereby carrying the carriage assembly in proximate spaced relationship to the platen for typing purposes. The pulley support assembly has its own cable tension adjusting means attached to the cable which can be adjusted separately to maintain the proper tension on the cable for proper carriage movement.
Further, inasmuch as the pulley support assembly is carrying the detachable carriage assembly, it is desirable and necessary that means be provided for adjusting the relative position of the carriage assembly with respect to the cylindrical platen. Normally this is done by adjusting the cylindrical platen in both vertical and horizontal planes. In the present invention, it is accomplished by a simple adjustment of the parallel support carrying the pulley support assembly whereby the parallel support is adjusted in a horizontal plane by a simple movement thus enabling the carriage assembly riding upon the pulley support assembly to also be moved in relationship to the cylindrical platen.